Heat exchanger for water and steam



(No Model.)

J. an G. WEIR. HEAT BXUHANGER FOR WATER AND STEAM.

UNITED V STATES PATENT OFFICE..

JAMES VVEIR AND GEORGE VEIR, OF OATIIOART, COUNTY OF RENFRE\V,

SCOTLAND.

HEAT-EXCHANGER FOR WATER AND STEAM.

SPECIFICATION forming part of Letters Patent No. 433,190, dated July 29, 1890.

Application filed April 8, 1890. Serial No. 347,134. (No model.) Patented in England April 25, 1887, No. 6,007.

T0 all whom it may concern:

Be it known that we, JAMES VVEIR and GEORGE VEIR, subjects of the Queen of Great Britain and Ireland, and residents of Oathcart, in the county of Renfrew, Scotland, lnwe invented an Improved Heat -Exchanger for Water and Steam, (for which We have obtained a British patent, No. 6,007, dated April 25, 1887,) of which the following is a specification.

Our said invention has for its object to increase the eliiciency ot apparatus for condensing steam or for heating or evaporating water by means of steam, the apparatus to which our improvements are applicable being of the kind in which the steam passes through a number of tubes, and being of special utility and value on board of stealnships, the main engin es ot which are worked with steam of the very high pressures now adopted, and are constructed to operate with three or more stages ot' expansion and with surface condensation. In such steamships the steam supplied by the main boilers is of a much higher pressure than is desirable for working auxiliary engines, Winches, windlasses, steering-engines, or other small motive-power apparatus, or for heating or cooking purposes, while at the same time it is inconvenient to have additional ordinary boilers working at lower pressures. According to our system, salt water may be evaporated by the heat of steam raised in the boilers for supplying the main engines, such steam being used for the said purpose either before or after being partly used in the main engines. The steam due to the evaporation of the salt water may be condensed for supplying fresh water, or, if of high enough pressure, it may be used or partly used in other apparatus of the same construction to raise steam from salt water to be condensed for supplying fresh water; or the steam raised from salt water may be led to the'main engines to work in the second-stage or later-stage cylinder or cylinders, so as to make up for any leakage or waste of steam from the main boilers; or, again, the steam raised from salt water may be used for working auxiliary engines or other motive-power apparatus or for circulating through pipes for heating saloons or other parts or for cooking or other purposes. In

general the steam passed into apparatus of the kind to which our invention relates has air associated with it, and if currents are not continually maintained through all the tubes the air accumulates and lodges in any tube in which there is little or no current, and renders such tube practically iueiiicient as a heat-exchanging medium. The steam becomes reduced in volume as it passes along the tubes, and as the tubes are ordinarily of equal area at both ends the discharge of water of condensation or of a mixture otv such water with vapor and air is necessarily comparatively slow; and it happens in practice that in certain circumstances little or no discharge takes place through some of a set of tubes, while steam may blow quite through others, which leads to air being accumulated in the tubes through which there is little or no current. Ineiiiciency due to the causes hereinbetore indicated is prevented or very much diminished by our improved apparatus, in which the steam is first led through a large proportion-ninety per centum, for example, of the tubes-and is subsequently led through the remainder.' This arrangement prevents any accumulation of steam or air at the disn charge ends of the larger portion of the tubes, andthereby insures continuous flow through all of them. In many cases, especially when the tubes are few in number, the desired ob ject may be attained by fixing rings or per forated plugs at the discharge ends of the tubes, so as to diminish the area at the discharge ends; or the device last described may be combined with the previously-described arrangement, in which what has passed through the larger proportion ot' the tubes is again passed through one or more tubes, in which it is subjected to further condensing action, so as to insure diminished pressure in the space into which-the larger proportion of the tubes discharge.

In carrying out our invention we employ apparatus or arrangements of parts, of which a simple example is shown on au accompany ing sheet of explanatory drawings, Figure l being an end elevation with part of a cover removed; Figs. 2 and 3, a longitudinal vertical section and a horizontal section of the ap- IOC) paratus. Figs. 4 and 5 are an enlarged end elevation and an enlarged vert-ical section of the discharge end of a tube.

The apparatus consists of a horizontal cylindrical vessel or boiler G, in the lower part of which are placed a number of tubes 7 8 9 for the high-pressure steam, which is to raise steam from salt Water. These tubes 7 8 9 are U-shaped in plan, and the two ends of each are fixed in a tube-plate 10 at one end of the boiler 6, a cover-plate 11 being bolted over the tube-plate 10. The tube-plate 10 is shaped to form three internal spaces 12 13 14, one 12 of which communicates with what may be called the inlet ends of the tubes 7, the discharge ends of these tubes 7 communicating with the space 14. Plugs 15, having small holes 16, Figs. 4 and 5, are fixed at these ends of the 4tubes 7, so as to diminish their area. The high-pressure steam is admitted by a pipe 17 and valve 18 to the inlet-space 12, and passes through the tubes 7 to the discharge-space 14. From this space 14 any remaining steam with the Water due to condensation and any air passes through the tube 8 to the middle space 13, and returns through the tube 9 to the final outlet 19, and in passing through the tubes 8 9 is again subjected to the cooling or condensing action of the Water or liquid in which the tubes 7 8 9 are immersed. By these means accumulation of air in the discharge-space 14 is prevented, pressure is kept low in that space, and currents through all the tubes are continuously maintained. The salt Water from which the steam is to be raised is admitted through a pipe and valve 21. The steam raised from the Water passes olf by an internal collectingpipe 22 and an external pipe 23, provided With a valve 24. The vessel 6 is provided with a surface blow-0E cock 20, a bottom-discharge or blow-off cock 25, sludge and man-hole doors 26 27, a relief-valve 28, a level gage-tube 29, and pressure-gages 30 3l. When the salt Water has, through evaporation, lbecome eX- cessively salt, it is discharged, While, when scale becomes attached to the tubes 7 S 9, it is detached by admitting high-pressure steam into them when they are cool.

1. A heat-exchanger` for Water and steam, comprising, in combination, a vessel to contain the Water, tubes for the passage of the steam and immersed in the Water, means for contracting the outlet ends of the said tubes, and a relatively small number of additional tubes, also immersed in the Water, and provided for the passage through them of any steam with air and Water of condensation discharged from the other tubes, all arranged and operating substantially as and for' the purposes herein set forth.

2. In heat-exchangers for Water and steam, tubes immersed in the Water for the passage of the steam, and having their outlet ends contracted, substantially as and for the purposes herein set forth.

In testimony whereof We have signed our names to this specification in the presence of two subscribing Witnesses.

JAMES WVEIR. GEORGE WEIR.

Vitnesses:

VEDMUND HUNT, DAVID FERGUSON. 

